The present invention pertains in general to facsimile networks and, more particularly, to a network for allowing a fax transmission at an originating end to be transmitted to a destination facsimile machine through the network.
Facsimile systems have seen increased acceptance in recent years and, in fact, have become a staple of the business community. In the early days of facsimile systems, some difficulties arose due to incompatibilities of the various systems. Even though one owned a facsimile system, there was some doubt as to whether a facsimile transmission could be completed to another system manufactured by a different manufacturer. This problem was somewhat alleviated when the standards were developed, one of those standards being the Group II standard.
Facsimile protocols are generally comprised of header information that is transmitted to a destination fax followed by an image, this typically being a bit-map image. However, prior to transmitting the header and images, it is necessary for a facsimile machine to negotiate a communication link with the destination facsimile machine. This is typically achieved to some type of hand-shaking. With Group II fax protocol, all too often the originating facsimile machines fail to even negotiate a communication link with the receiving facsimile machine.
When the Group III protocol was introduced in the mid-1980""s, the use of facsimile machines saw a rapid increase in use. This was due to the fact that the Group III protocol not only was backward compatible with Group II, but it enabled a high level of standardization to occur in the industry. Typically, a Group III facsimile has associated therewith a handshake protocol that allows the two facsimile machines to determine their combined speed of operation and then transmit the images at that determined or negotiated speed. This is an interesting aspect of the facsimile machine, in that facsimile machines are typically rated at 14.4 Kbs, but this is their maximum speed. All too often, due to noise on the phone line, etc., the facsimile machines will default down to a slower speed. Typically, they initially try to effect the communication link at 9,600 Kbs and then drop to 4,800 Kbs, then 2,400 Kbs, 1,200 Kbs, and so forth, until an error free speed is reached. It is feasible with very noisy lines that a facsimile system may communicate at as low a baud rate as 300 Kbs. However, once an acceptable noise-free communication link can be maintained, then the image is transmitted at that speed, with both the source and destination adjusting their speed to the same speed.
In a Group III fax, the transmission of the image over the negotiated transmission link will consist of first transmitting the header and then all of the pages in the original facsimile document as a single job. Typically, there is an End of Page (EOP) command sent at the end of each page and then an End of Job (EOJ) command sent at the end of the job. During transmission, there are various error correction algorithms utilized to correct the data when it is transmitted, but some applications of the Group III fax has one disadvantage in that if the last page is not received correctly by a receiving fax, it does not provide an acknowledgment to the sending fax that it has received the entire job and the sending fax may interpret this to require a re-send operation, wherein the entire document is re-sent. For small jobs that are only one or two pages long, this is not a problem. However, for large jobs in excess of two hundred pages, this can be quite time consuming. The time consuming aspect is, of course, the time it takes to transmit a single page.
Transmission of an image over a facsimile connection is facilitated by first converting the image into a bit-mapped image via scanning of a hard copy of the document or converting a print job in a computer directly to the image, and then transmitting the individual bits as they are scanned or generated in a serial manner. However, this transmission of images is time consuming, especially if the image includes a lot of dark areas. One solution to this has been to actually transmit the data file prior to transforming it into an image. For example, one system that has achieved this is referred to as the Microsoft Exchange Server(copyright), which is an operating system for messaging and file sharing. The purpose of this system to alleviate the necessity to transfer a document into an image prior to transmission to a remote site. It is not the conversion into the image that is time consuming but, rather, it is the transmission of the image information. Further, on the receiving end, the image information is not readily translated into a data file that can be manipulated. For example, if a destination user desired to transmit a contract which basically comprised an ASCII file, the procedure is to convert it first into an image and then transmit the image to the destination system. Once the destination system receives this image, it must be printed out from a facsimile machine or, alternatively, it can be imported into a computer program which can then either print the image out on a standard printer or store the image. However, once the image is received, it is not in a useable form to allow modification of the document itself. With the digital transmission systems, the file itself can be transmitted without first converting it into an image. However, all facsimile systems that exist at present require conversion of a file into an image as it would appear in a printed document and then transmission of this image. This can be facilitated by fax modems that directly convert a file into an image while using a scanner, the scanner being the more conventional approach.
The present invention disclosed and claimed herein is a method and apparatus for transmitting a fax from an originating fax machine to a destination fax machine. The system includes a first network for receiving a fax transmission that is routed thereto by the fax source. The fax source is operable to generate the fax transmission by assembling the information into an appropriate fax transmission and transmitting it over the first network. A buffer node is interfaced with the first network for receiving the fax transmission therefrom. The buffer node includes a buffer storage area for storing at least a portion of the received fax transmission. It also includes a fax transmission device for initiating a fax connection over a second network to the destination fax system. A fax delivery system then delivers the received fax transmission at the buffer node to the destination fax system. A status device at the buffer node is operable to determine the status of the fax delivery by the fax delivery system to the destination fax system. A status feedback device then forwards the status information to the fax source through the first network during the delivery operation of the fax transmission to the destination fax by the fax delivery device. The fax source has associated therewith a storage area for storing the received status information.
In another aspect of the present invention, the first network includes a public switched telephone network (PSTN) and the fax source includes a fax system that is operable to send a fax transmission over the PSTN in a format compatible therewith. The first network includes a global data network interfaced with the buffer node. An intermediate node is provided for interfacing with the PSTN and receiving the fax transmission thereover. A translation device at the intermediate node is operable to transmit the received fax transmission for a protocol compatible with the PSTN to a protocol compatible with the global data network. The intermediate node includes a compression device for compressing the translated information prior to transmission to the buffer node. The buffer node further includes a decompression device for decompressing the received fax transmission. Further, the intermediate node can also encrypt the translated information prior to transmission to the buffer node. This requires the buffer node to then include a decryption device for decrypting the received transmission.
In yet another aspect of the present invention, the fax transmission device is operable to initiate the fax connection prior to receipt of all of the received fax transmission by the buffer node. This initiation operation can have a length of time that is variable.
In a further aspect of the present invention, the fax delivery device has associated therewith a delay device for delaying the delivery of select portions of the fax transmission during transmission thereof to the destination fax system by the fax delivery device. This delay device includes an insertion device for inserting information within the facsimile transmission during transmission thereof to increase the length of the facsimile transmission over that of the received facsimile transmission by the buffer node. In this manner, the facsimile transmission can be modified during transmission thereof to the destination fax system.
In a yet further aspect of the present invention, the network includes a central network having multiple paths for transmitting data between remote locations with the transmission path of the data from a first point to a second point over the network being determined by the central network. A plurality of network nodes is provided to interface with the central network and are disposed at remote locations. Each of the network nodes has a PSTN interface for interfacing with a public switch telephone network (PSTN) that is local to each of the nodes. The interface is operable to transmit and receive fax transmissions thereover. The network interface device interfaces with the central network and then transmits and receives network transmissions thereover. A receive/transmit device is provided for communicating with a fax device that is connected to the PSTN and is interfaced through the PSTN interface to receive facsimile transmissions therefrom and transmit facsimile transmissions thereto. The fax receive/transmit device is operable to receive destination information from the fax device defining the address of a destination fax device and the fax receive/transmit device is also operable to effect a transmission of the fax in accordance with a stored destination address of a fax device associated with the PSTN to which the receive/transmit device is interfaced. A buffer is provided at each of the nodes for storing at least a portion of the received fax transmission by the fax receive/transmit device. These are then converted from the protocol associated with the received fax to a predetermined network format during a transmission operation and from the network format to the fax format during a receive operation from the central network. A network transmit/receive device is provided for transmitting network information converted by the conversion device over the central network through the network interface device and also for receiving fax transmissions from the central network through the network interface device. A routing device is provided at each of the nodes for determining a route over the central network in one of the multiple paths associated therewith, which routing determines which one of the nodes other than the originating one of the nodes is to receive the network information. The routing device is operable to establish a communication link to the other of the nodes for transmission of network formatted information over the established communication link.